Random String Generator
Generate random strings with custom characters, for free.
This tool runs entirely in your browser. Your files are never uploaded to a server.
What this tool does
Generates one or more random strings built from the character types you choose — uppercase letters, lowercase letters, numbers, and symbols — useful for test data, temporary IDs, or sample values.
How to use it
Set a length (1 to 128 characters) and how many strings to generate (1 to 100), check the character types you want included, then click Generate. The results appear one per line in the output box, and Copy places all of them on your clipboard at once.
Worked example
With the defaults — length 16, uppercase, lowercase, and numbers checked, symbols unchecked — each character is drawn from a 62-character pool (26 + 26 + 10), producing strings like 7bKq2ZpXt9LmR3Fw. Checking symbols too widens the pool with !@#$%^&*()_+-=, adding punctuation into the mix.
Method
For each character position, the tool draws one 32-bit value from the browser's crypto.getRandomValues(), reduces it modulo the size of your selected character pool, and picks that character. This is the same cryptographically secure API used by the Password Generator, just applied to produce many independent strings at once instead of one.
Character sets and limits
The four selectable sets are uppercase A–Z, lowercase a–z, digits 0–9, and the symbols !@#$%^&*()_+-=. At least one set must stay checked, or the Generate button is disabled since there's no pool to draw from. Length is capped at 128 characters and count at 100 strings per generation.
Limitations
Because each character is chosen with value % pool.length rather than rejection sampling, character sets whose size doesn't evenly divide 2^32 carry a theoretical selection bias — far too small to matter for test data or identifiers, but worth knowing if you need provably uniform output. The symbol set is fixed and can't be customized beyond the four built-in categories.
Privacy and processing
All strings are generated locally in your browser using the Web Crypto API. Nothing you configure or generate is uploaded to a server.
Frequently Asked Questions
- How is this different from the Password Generator?
- Same secure randomness, but this tool is built for generating many strings at once (e.g. test data, IDs).
- Is my data uploaded anywhere?
- No, everything is generated locally in your browser using the Web Crypto API.
- What character sets can I include?
- Uppercase letters (A–Z), lowercase letters (a–z), numbers (0–9), and a fixed symbol set (!@#$%^&*()_+-=). At least one must be checked, or generation is disabled.
- What are the length and count limits?
- Up to 128 characters per string and up to 100 strings per click, to keep the tool fast and prevent abuse.